0.4.3-RC1 (2022-01-04)

We’re happy to announce the release of Scala Native v0.4.3-RC1, which brings support for Scala 3. This release does also contain performance-critical bug fixes to performing operations on Strings, leading to significant improvement of regexes throughput.

Due to multiple internal changes and to ensure compatibility with libraries published using Scala 2.13, we’ve decided that the 0.4.3 will be preceded by release candidates. If no new bugs will be discovered until 17th January 2022 it would be promoted to a full release.

Breaking changes

The minimal version of Scala 3 supported by Scala Native is 3.1.0, due to fatal blockers in Scala 3.0.x.

Changes to the main method resolving

In the previous versions of Scala Native main entry point was always resolved based on the companion object defining the main method. This behaviour however lead to multiple issues in situations when an actual main method was introduced via inheritance. Because of that issue, build tools needed to always add $ suffix to actual main class to make sure that entry method would be found. With the 0.4.3 release, Scala Native does generate static method forwarders in the same way as it is done in JVM and Scala.js. Build tools should make sure to no longer add $ to the discovered main class name.

Source compatibity of stackalloc[T] and alloc[T] methods

No-param methods scalanative.unsafe.stackalloc[T] and scalanative.unsafe.alloc[T] were removed from Scala 3 unsafe package. In Scala 2 these methods have been deprecated and it is recommended to use empty-param variants of these methods instead, eg. scalanative.unsafe.stackalloc[T](). This change was introduced due to changes of how does Scala 3 interpret source code as it could lead to dangerous, hard to debug, runtime errors. As an example call to stackalloc[Byte](10) in Scala 2 would result in allocating memory of size 10 * sizeof(Byte). In Scala 3 however, the given snippet would be interpreted as stackalloc[Byte].apply(10) which is still valid, but leads to allocating 1 * sizeof(Byte) chunk of memory and accessing its 10th element, which would lead to undefined behaviour. More information can be found in #2480

Known issues

Cannot create documentation using scaladoc in Scala Native sbt project

When trying to generate documentation using Scaladoc for projects using Scala Native compilation would fail with an exception. This issue is common for most of the compiler plugins and was already fixed in Scala 3.1.1-RC2 compiler. As a workaround in Scala 3.1.0 we would recomend adjusting sbt build, by filtering out all -Xplugin settings from Compile / doc / scalacOptions.

Commits since last release 40
Merged PRs 40
Contributors 5


Big thanks to everybody who contributed to this release or reported an issue!

$ git shortlog -sn --no-merges v0.4.2..v0.4.3-RC1
    34	Wojciech Mazur
     3	Eric K Richardson
     1	Anton Sviridov
     1	Jan Chyb
     1	Lorenzo Gabriele

Merged PRs

v0.4.3-RC1 (2022-01-04)

Full Changelog

Merged pull requests:

Bug fixes

  • Initialize _String with _ Array[Char] #2449 (lolgab)

  • Fix ARM64 MacOS varargs #2448 (keynmol)

  • Fix certain absolute file paths being shown as relative on Windows #2471 (jchyb)

  • Make java.nio.MappedByteBuffer JDK9+ compliant #2453 (WojciechMazur)

  • Remove redundant coversion of CharSequence into Array in Character.codePoint{at, before} methods #2495 (WojciechMazur)


Native library

Compiler plugin / NIR